Download Proposed Revisions to Draft of TIA-968-B

Telecommunications Industry Association
TR41.9.1-06-11-004M
Document Cover Sheet
Project Number
Document Title
Proposed Revisions to TIA-968-B.
Source
Verizon
Contact
Trone Bishop
Verizon
13100 Columbia Pike 6E
Silver Spring, MD 20904
Distribution
TR-41.9.1
Intended Purpose
of Document
(Select one)
X
Phone: 301-236-3754
Fax: 301-989-6505
Email: [email protected]
For Incorporation Into TIA Publication
For Information
Other (describe) Notices
The document to which this cover statement is attached is submitted to a Formulating Group or subelement thereof of the Telecommunications Industry Association (TIA) in accordance with the provisions
of Sections 6.4.1–6.4.6 inclusive of the TIA Engineering Manual dated March 2005, all of which
provisions are hereby incorporated by reference.
Abstract
This contribution provides comments and proposes changes to the draft of TIA-968-B. The comments and
proposed changes are provided to the TR41.9.1 working group as a basis for discussion and should not be
construed as binding on Verizon. Verizon specifically reserves the right to amend or modify the material
contained herein after receiving input from subcommittee members and further review.
v1.0 – 20050426
Telecommunications Industry Association
TR41.9.1-06-11-004M
Introduction
This contribution provides comments and proposes changes to the draft of TIA-968-B provided
by the editor in contribution TR41.9-06-08-005-L. The comments and proposed changes are
provided to the TR41.9 subcommittee as a basis for discussion and should not be construed as
binding on Verizon. Verizon specifically reserves the right to amend or modify the material
contained herein after receiving input from subcommittee members and further review.
Comments and Proposed Revisions to Draft of TIA-968-B
1- Clause 1.1 - Revise bullet item (j) to accommodate other types of DSL.
j) Of all terminal equipment to ADSL services and other DSL services (including ADSL2+,
SHDSL, VDSL2, etc).
2- Clause 4.3 - The Leakage Current Limitation in clause 4.3 is not clearly stated, the clause
contains no subclauses, and the requirements and test procedures are stated in notes to Table 4.1.
Recommend rewriting this clause in the following manner:
4.3.
Leakage Current Limitations
Leakage current shall not exceed 10 mA peak at any time during the 90-second test interval
described in 4.3.1 when the 50-60 Hz AC test voltage in Table 4.1 is applied as described in 4.3.1
between the test points in Table 4.1. The 10 mA peak maximum leakage current limitation may
be increased as described in 4.3.6 to accommodate cable capacitance associated with multi-unit
equipment. (Editor’s note - This text is based on note 1 of Table 4.1)
4.3.1
Test Interval
The 90-second leakage current test interval shall consist of a 30-second time period during which
the test voltage applied between the points in Table 4.1 is gradually increased from zero to the
maximum value listed in Table 4.1 followed immediately by a 60-second time period during
which the test voltage is maintained at the value listed in Table 4.1. (Editor’s note - This text is
based on note 1 of Table 4.1)
4.3.2
Equipment States
Equipment states necessary for compliance with the requirements of this section, that cannot be
achieved by normal means of power, shall be achieved artificially by appropriate means.
(Editor’s note - This text is from note 2 of Table 4.1)
4.3.3
Treatment of Filters and Use of Alternative Voltage
Filter paths, such as capacitors used in EMI filters, are left in place during leakage current testing,
since these components can be a path for excessive leakage. (Editor’s note - This text is from note
5 of Table 4.1)
RF filters and surge protectors on the line side of power supplies may be disconnected before
making leakage current measurements. (See 4.3.4)
As an alternative to disconnecting RF filters and surge protectors, the leakage current
measurement may be made using a DC voltage equal to the peak AC test voltage. (Editor’s note This text is from note 7 of Table 4.1)
4.3.4
Removal of intentional DC path to ground used for protection purposes.
A telephone connection, power lead, auxiliary lead, or E&M lead that has an intentional DC
conducting path to earth ground for protection purposes at the leakage current test voltage (such
v1.0 – 20050426
Telecommunications Industry Association
TR41.9.1-06-11-004M
as through a surge suppressor), may have the component providing the conducting path removed
from the equipment for the leakage current test in that operational state. Components removed for
this reason shall comply with the requirements of Section 4.4.5.2. (Editor’s note - This text is
from note 4 of Table 4.1. The phrase “power lead” was added in the first sentence for
consistency with CS-03 Part 1. )
4.3.5
Exclusion for intentional DC conducting path to ground.
A telephone connection, auxiliary lead, or E&M lead that has an intentional DC conducting path
to earth ground at operational voltages (such as a ground-start lead), may be excluded from the
leakage current requirement in that operational state. The Tip Ground state of loop-start CentralOffice-implemented telephones is another example of a lead that may be excluded. Leads
excluded for this reason shall comply with the requirements of Section 4.4.5.1. (Editor’s note This text is based on note 3 of Table 4.1. The sentence mentioning the tip ground state was added
for consistency with TSB-31-C.)
4.3.6
Multi-unit equipment interconnected by cables.
For multi-unit equipment interconnected by cables, that is evaluated and approved as an
interconnected combination or assembly, the specified 10 mA peak maximum leakage current
limitation, other than between power connection points and other points, may be increased as
described here to accommodate cable capacitance. The leakage current limitation may be
increased to (10N+0.13L) mA peak where L is the length of the interconnecting cable in the
leakage path in meters and N is the number of equipment units that the combination or assembly
will place in parallel across a telephone connection. (Editor’s note - This text is from note 6 of
Table 4.1)
For clarity, move the list of connections appearing before Table 4.1 should be moved into Table
4.1. The references to various notes have been removed since that information is now found in the
text of Clause 4.3.
v1.0 – 20050426
Telecommunications Industry Association
TR41.9.1-06-11-004M
Table 4.1 Voltage Applied For Various Combinations of Electrical Connections
Voltage source connected between
Vac rms*
(a) and (b)
(a) and (c)
(a) and (d)
(a) and (e)
(a) and (f)
(a) and (g)
(b) and (c)
(b) and (d)
(b) and (e)
(b) and (f)
(b) and (g)
(c) and (e)
(c) and (f)
(d) and (e)
(d) and (f)
(e) and (f)
1500
1000
1000
1000
1000
1000
1500
1500
1500
1500
1500
1000
1000
1000
1000
1000
(a) All telephone connections;
(b) All power connections;
(c) All possible combinations of exposed conductive surfaces
on the exterior of such equipment or circuitry including
grounding connection points, but excluding terminals for
connection to other terminal equipment;
(d) All terminals for connection to approved protective
circuitry or nonapproved equipment;
(e) All auxiliary lead terminals;
(f) All E&M lead terminals, and
(g) All PR, PC, CY1 and CY2 leads.
*Value to which test voltage is gradually increased (See 4.3.1)
3. Clause 4.5.2.2.1 - For clarity, identify coin deposit signals as an example of signals generated
by terminal equipment that are used for network control.
4.5.2.2.1 For all operating conditions of approved terminal equipment and approved protective
circuitry, the maximum power in the frequency band below 3995 Hz delivered to a loop simulator
circuit shall not exceed the following when averaged over any 3-second interval:
a) 0 dBm when used for network control (e.g., DTMF and Coin Control signals);
b) 0 dBm when DTMF is used for manual entry end-to-end signaling. When the device is used for
this purpose it shall not generate more than 40 DTMF digits per manual key stroke;
c) -9 dBm in all other cases.
v1.0 – 20050426
Telecommunications Industry Association
TR41.9.1-06-11-004M
4. Clause 4.5.2.4.1 - The connector wiring configurations in TIA-EIA-IS-968 were dropped when
TIA-968-A was developed. Embedded in the wiring configurations were a few requirements for
data terminal equipment using external programming resistors to control signal levels. To restore
the dropped requirements, add the following text to clause 4.5.2.4.1:
4.5.2.4.1 Data circuit terminal equipment intended to operate with a programming resistor for
signal level control shall provide not exceed the programmed levels given in Table 4.5 within +/1 dB. The voltages impressed on resistor Rp by the data equipment shall be such as not to cause
power dissipation in Rp in excess of 50 milliwatts. The circuit shown below was used in
calculating values of the programming resistors and may be useful in implementing the automatic
control of signal power output in the programmed data equipment.
< Insert the figure from page 139 of TIA-EIA-IS-968 >
R1 is the source impedance for the input signal Vin, and also the terminating impedance of the
load. RS is a series resistance, on which the computation of the programming resistor Rp is based.
The table of values of Rp is derived for R1=600 ohms; RS=3600 ohms.
5- Clause 4.6.2.1 - The transverse balance limitations of this clause, which are normally
applicable to all states of loop-start devices, should not be applied to the Tip Ground state of
loop-start Central-Office-implemented telephones per TSB-31-C. Recommend revising this
clause as shown below:
4.6.2.1 For analog one-port 2-wire terminal equipment with loop-start, ringdown, or inband
signaling or for voiceband metallic channel applications, both off-hook and on-hook requirements
shall apply. The Tip Ground state of loop-start Central-Office-implemented telephones is
excluded from this requirement.
6- Annex A - The grandfather clauses in Annex A are specific to the U.S. but not applicable to
Canada. An explanation might be helpful.
A.1 Introduction
The grandfather provisions in this Annex were originally contained in Part 68 of the FCC Rules.
These grandfather provisions provide an alternative whereby certain nonapproved TE can be
directly connected to wireline carrier networks in the United States during a limited transition
period. Clauses A.2 through A.11 provide the grandfather conditions in the U.S. for various types
of TE.
7- Add the following general requirement in the scope of TIA-968-B:
The adjustments of any real or virtual control that is readily accessible by, or intended to be
accessible to the user, either locally or remotely, shall not cause the TE to become non-compliant
with this standard.
8- Foreword: Add the following new foreword or something similar:
FOREWORD
(This foreword is not part of this Standard.)
The Federal Communications Commission (FCC), in its Report
& Order, FCC 00-400, on CC Docket No. 99-216, mandated
creation of the Administrative Council for Terminal Attachments
(ACTA). In 47 CFR 68.7(b) ACTA was charged to adopt and
v1.0 – 20050426
Telecommunications Industry Association
TR41.9.1-06-11-004M
publish technical criteria to prevent harms to the telephone
network submitted to it by standards development organizations
accredited by the American National Standards Institute (ANSI).
The first version of this document was an interim standard (IS)
whose contents were identical to the criteria in Part 68 of Title
47 of the Code of Federal Regulations at the time the Report &
Order was issued. The document was advanced from an IS to an
ANSI approved standard with the publication of TIA-968-A in
2002. Four addendums were subsequently published: TIA-968A-1-2003, TIA-968-A-2-2004, TIA-968-A-3-2004, and TIA968-A-4-2006.
This standard, TIA-968-B, is based on the text from TIA-968-A
and addendums A-1, A-2, A-3 and A-4. It also includes the
following changes:
1- Clause 4.3 (Leakage Current Limitations) was rewritten for
clarity but the requirements remain the same
2- Coin deposit signals were added to 4.5.2.2.1 along with
DTMF as examples of signals generated by terminal
equipment that are used for network control.
3- Requirements that were inadvertently deleted in TIA-968-A
have been restored in 4.5.2.4.1 for data circuit terminal
equipment intended to operate with a programming resistor
for signal level control.
4- Clarified in 4.6.2.1 that the Tip Ground state of loop-start
Central-Office-implemented telephones does not require
transverse balance testing.
5- Clarified in the scope that terminal equipment must comply
with the applicable technical criteria of this standard at any
control adjustment that is employed.
6- Annex A was clarified by limiting the grandfather clauses
for non-approved equipment to the United States.
7- Etc….
This standard was produced by Subcommittee TR-41.9,
Technical Regulatory Considerations. It was developed in
accordance with ANSI and TIA/EIA procedural guidelines and
represents the consensus position of the Working Group and its
parent Subcommittee, which served as the formulating group. It
has also received the concurrence of Engineering Committee
TR-41, User Premises Telecommunications Requirements.
Committee approval of this standard does not necessarily imply
that all members voted for its approval.
v1.0 – 20050426